Ballistic device comprising a projectile and its launcher

ABSTRACT

A BALLISTIC DEVICE COMPRISES A PRJECTILE AND A LAUNCHER THEREFOR, THE PROJECTILE HAVING A TUBE AT TIS REAR END IN THE FORWARD END OF WHICH A PROPULSIVE CHARGE IS COMPRESSED BY A PISTON. THE PISTON IS BACKED BY A GUIDE ROD ON THE LAUNCHER WHICH EXTENDS INTO THE TUBE, SO THAT UPON FIRING, THE TUBE IS DRIVEN FORWARDLY RELATIVE TO THE PISTON WHILE THE PISTON BEARS AGAINST THE GUIDE ROD. THE CHARGE IS ELECTRICALLY FIRED, AND THE ELECTRICAL CONNECTION EXTEND THROUGH THE PISTON AND ALONG THE GUIDE ROD.

Oct. 5, 1971 R. BORNAND 3,610,091

BIIJLISTIC DEVICE COMIRISING A PROJECTILE AND ITS LAUNCIIER Filed Feb.1o, 1969 05597 me/mwa United States Patent O 3,610,091 BALLISTIC DEVICECOMPRISING A PROJECTILE AND ITS LAUNCHER Robert Bornand, Meyrin, Geneva,Switzerland, assigner to Transurvey Holding Company Inc. Filed Feb. 10,1969, Ser. No. 798,058 Claims priority, application Switzerland, Feb. 8,1968, 2,075/ 68 Int. Cl. F41f 1/06 U.S. Cl. 89-1 F 8 Claims ABSTRACT FTHE DISCLOSURE The present invention relates to a ballistic devicecornprising a projectile and its launcher, the projectile cornprising arearwardly extending tube which is radially indeformable under thepressure developed during burning of a launching charge and which ishermetically sealed axially by a piston. The launcher comprises a guiderod in contact with the piston and ignition means for the launchingcharge, characterized in that the said ignition means is electrical innature and is disposed at least in part in the piston and is externallyactuated by means of the guide rod.

The attached drawing shows, by way of example, one embodiment of adevice according to the invention, in which the projectile is in theform of a self-propelled grenade.

In the drawing:

FIG. l is a View partially in axial section, with the parts in theirposition immediately before firing;

FIG. 2 is a view partially in elevation, with parts in axial section inthe position they occupy after firing, when the grenade is just leavingthe guide rod which forms a portion of the launcher; and

FIG. 3 is an axial cross-sectional View to a larger scale of a portionof FIG. 1 showing in detail the ignition means for the launcher charge.

Referring now to the drawing in greater detail, the illustratedballistic device comprises a self-propelled projectile comprised by ahead 1 which is screwed on the forward externally screw-threaded portion2a of a tube 2 whose rear portion carries fins 2b as well as ascrewthreaded annular retaining ring 3. Immediately behind the portion2a of tube 2 is disposed au explosive charge 4 which is compressed by ametal piston 5 which may for example be of brass and which is forcefitted into the recess in tube 2 from the rear end of tube 2 beforeretaining ring 3 is added. The pressure exerted by piston 5 may forexample be 400 to 800 kg./crn.2. The apparent volume of explosive charge4, including the interstices between the powder grains, thereforeentirely lls the space between the rear wall of portion 2a and thepiston 5.

Piston 5 is traversed by an axial hole, in the rear portion of which isdisposed a pin 6 of electrically insulating material, in which in turnis screwed a cylindrical brass rod 7 which bears against an insulatingplug 8 which hermetically closes the forward end of the axial hole. Theplug S is traversed by a tail 9a of a brass capsule 9 containing apowdered primer and a metallic filament (not 3,610,091 Patented Oct. 5,1971 shown) which glows incandescent upon electrical resistance heating.The body of capsule 9 is for the most part surrounded by a steel ring 10while the tail 9a is screwed into the brass rod 7.

In the rear or lower portion of the bore of the insulating pin 6 isdisposed a hollow brass contact 11 which is acted upon by a compressionspring 12 that also bears against rod 7, so that the head of contact 11emerges somewhat from the rear wall of piston 5, this rear wall in turncomprising the bottom of a rearwardly opening cylindrical seat formed inpiston 5.

In the rear cylindrical seat thus formed in piston SV is disposed,before the ignition of the launcher charge, the forward end of a steelguide rod 13 whose rear head 13a is provided with screw threadingpermitting it to be screwed into a support forming part of the launcherproper' (not shown) or which may be connected by an adapter to themuzzle of any desired firearm. The forward end of the guide rod 13 isprovided with a recess lined with a cup 14 of insulating material at thebottom of which is disposed a contact lug 15 of stainless steel whosepurpose is to establish electric contact with the portion of the contact11 that emerges from piston 5. An electric wire 16 Whose forward end issoldered to the contact lug 15 extends the length of guide rod 13 in alongitudinal slot 17 which is lined with insulating material and whichcommunicates, by a bore directed toward the axis of the rod and linedwith an insulating tube 18, with the seat containing the contact lug 15.The rear or lower end of the wire 16 passes through the head 13a in anaxial bore lined with an insulating tube 19 and is pressed by a setscrew 20 screwed into an insulating sleeve 21 against the interior wallof a contact 22 disposed in the insulating sleeve 21. The contact 22 isconnected by a conductor 23 to the positive pole of a current source 25,while the head 13a is connected by a conductor 24 to the negative poleof the said current source across a switch 2'6.

The rod 13 is disposed to guide the tube 2 on the one hand in the boreof the retaining ring 3 and on the other hand in the rear seat of thepiston. According to another embodiment of the invention (not shown),the retaining ring 3 could be omitted and the rod 13, whose diameterwould accordingly be somewhat less than that of the piston 5, would befreely slidably disposed directly in the tube 2.

The operation of the ballistic device is as follows:

The parts being in the position shown in FIG. 1, preparatory tolaunching the self-propelled projectile 1, 2, all that need be done isto close the switch 26 to establish an electric current between thecontact lug 15 and the contact 11 so that a circuit is completed, on theone hand, through contact 11, spring 12, rod 7, tail 9a and one end ofthe filament in capsule 9, and on the other hand, through head 13a, rod13, piston 5, ring 10, capsule 9 and the other end of the filament incapsule 9. The filament in capsule 9 will thus be. brought toincandescence by electric resistance heating and will fire the primer,which in turn will rlire the launching charge 4 which explodes, exertingon the piston 5 maintained fixed by the guide rod 13 a pressure which isinitially quite great. Under the influence of this pressure, the tube 2secured to the head 1 of the projectile is projected forwardly in thedirection of the arrow F in FIG. 2, while the piston 5 is forced againstthe forward end of rod 13; and when the tube 2 leaves the rod 13, asseen in FIG. 2, the piston 5 will be retained in the rear end of tube 2by the retaining ring 3. The tight fit of piston 5 in tube 2 seals therear end of tube 2 against the escape of gas. The length of the tube 2is so adjusted that the acceleration of the projectile with respect tothe guide rod 13 will be practically over when the tube leaves the guiderod 13. The full acceleration of the projectile therefore correspondssubstantially to the practically total combustion of the explosivecharge 4.

Although the present invention has been described and illustrated inconnection with a preferred embodiment, it is to be understood thatmodifications and variations may be resorted to without departing fromthe spirit of the invention, as those skilled in this artvwill readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the present invention as defined by theappended claims.

Having described my invention, I claim:

1. In a ballistic device comprising a projectile and a launcher for thatprojectile, the projectile comprising a rearwardly extending tubecontaining a combustible charge sealed in the tube by means of a piston,the launcher comprising a guide rod that extends forwardly into the tubeand bears against the rear of the piston, and electrical ignition meansfor the launching charge; the improvement in which the piston is forcefitted into the tube, an ignition capsule disposed at least in part in arecess of the piston adjacent the charge with a shoulder of the capsuleresting on the bottom of the recess, the piston having an axial boretherein, a pin of insulating material disposed in the bore, conductormeans extending along the piston and through said insulating pin andelectrically interconnecting a source of electricity in said ignitioncapsule to ignite a primer in said capsule when said conductor means iselectrically charged, said guide rod having a recess in its forward end,insulating material lining the last-named recess, said conductor meanscomprising a conductive metal plug disposed in said last-named recessand surrounded by said insulating material, and electrically conductivemeans extending through said insulating pin and releasably electricallycontacting said plug for connecting said plug electrically with saidprimer when the rear of the piston bears against the forward end of saidguide rod.

2. A ballistic device as claimed in claim 1, the rstmentioned saidrecess being disposed on the axis of said piston and opening in an axialdirection away from said guide rod.

3. A ballistic device as claimed in claim 1, said means extendingthrough said insulating pin including means slidably disposed in thepin, and spring means urging said slidably disposed means against andinto electrical contact with said plug.

4. A ballistic device as claimed in claim 1, said conductor meansincluding an electric wire extending lengthwise within but insulatedfrom said guide rod.

5. A ballistic device as claimed in claim 1, said conductor meansincluding an incandescent wire in contact with said primer.

6. A ballistic device as claimed in claim 4, in which said wire isdisposed in a longitudinal groove in said guide rod, said groove beinglined with insulating material.

7. A ballistic device as claimed in claim '6, said wire extending fromsaid groove through a passageway directed inwardly toward the axis ofthe guide rod and being electrically secured to a contact disposedaxially of but electrically insulated from the rear end of said guiderod.

8. A ballistic device as claimed in claim 7, said wire extendinginwardly from said groove toward the axis of said guide rod at theforward end of said guide rod and being in electrical contact with aplug that is disposed in but electrically insulated from the forward endof said guide rod.

References Cited UNITED STATES PATENTS 1,034,160 7/1912 Starkweather102-46 1,347,125 7/1920 Schneider 89-1.3 2,931,299 4/1960 Sokolowski102-46 X 3,068,755 12/1962 `lohnstone et al. 89-1.3 3,134,330 5/1964Batou 89-1.3 X 3,365,828 1/1968 Badali et al 421 F SAMUEL W. ENGLE,Primary Examiner U.S. Cl. X.R.

42-1 F; 89-28; IGZ-46, 49.1

